JP3546913B2 - Chemically amplified positive resist material - Google Patents

Description

（式中Ｒ^１、Ｒ^２はそれぞれ独立して水素原子又は炭素数１〜１０の直鎖状、分岐状もしくは環状のアルキル基を示し、Ｒ^３は炭素数１〜１０のヘテロ原子を有していてもよい１価の炭化水素基を示し、Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^２とＲ^３は環を形成してもよく、環を形成する場合にはＲ^１、Ｒ^２、Ｒ^３はそれぞれ炭素数１〜１０の直鎖状又は分岐状のアルキレン基を示す。）
【００１３】
〔ＩＩ〕：（Ａ）有機溶剤、
（Ｂ）フェノール性水酸基の水素原子の１０モル％以上が下記一般式（１）で示される酸不安定基によって置換され、かつフェノール性水酸基の水素原子の０モル％を超える割合で下記一般式（２ａ）又は（２ｂ）で示されるＣ−Ｏ−Ｃ基を有する架橋基により分子内及び／又は分子間で架橋されている重量平均分子量５，０００〜１００，０００のベース樹脂、
（Ｃ）酸発生剤、
（Ｄ）常圧７６０ｍｍＨｇでの沸点が１８０℃以上の炭素数２〜２０の２〜４価のアルコール化合物
を含有することを特徴とする化学増幅ポジ型レジスト材料。
【００１４】
【化６】

（式中Ｒ^１、Ｒ^２はそれぞれ独立して水素原子又は炭素数１〜１０の直鎖状、分岐状もしくは環状のアルキル基を示し、Ｒ^３は炭素数１〜１０のヘテロ原子を有していてもよい１価の炭化水素基を示し、Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^２とＲ^３は環を形成してもよく、環を形成する場合にはＲ^１、Ｒ^２、Ｒ^３はそれぞれ炭素数１〜１０の直鎖状又は分岐状のアルキレン基を示す。）
【００１５】
【化７】

（式中、Ｒ^４、Ｒ^５は水素原子又は炭素数１〜８の直鎖状、分岐状又は環状のアルキル基を示す。又は、Ｒ^４とＲ^５とは環を形成してもよく、環を形成する場合にはＲ^４、Ｒ^５は炭素数１〜８の直鎖状又は分岐状のアルキレン基を示す。Ｒ^６は炭素数１〜１０の直鎖状又は分岐状のアルキレン基、ｂは０又は１〜１０の整数である。Ａは、ａ価の炭素数１〜５０の脂肪族もしくは脂環式飽和炭化水素基、芳香族炭化水素基又はヘテロ環基を示し、これらの基はヘテロ原子を介在していてもよく、またその炭素原子に結合する水素原子の一部が水酸基、カルボキシル基、カルボニル基又はフッ素原子によって置換されていてもよい。Ｂは−ＣＯ−Ｏ−、−ＮＨＣＯ−Ｏ−又は−ＮＨＣＯＮＨ−を示す。ａは２〜８、ａ’は１〜７の整数である。）
【００１６】
〔ＩＩＩ〕：（Ａ）有機溶剤、
（Ｂ）上記〔Ｉ〕又は〔ＩＩ〕記載のベース樹脂、
（Ｃ）酸発生剤、
（Ｄ）常圧７６０ｍｍＨｇでの沸点が１８０℃以上の炭素数２〜２０の２〜４価のアルコール化合物、
（Ｅ）下記一般式（３Ｄ）で示される繰り返し単位を有する重量平均分子量が３，０００〜３００，０００の高分子化合物
を配合したことを特徴とする化学増幅ポジ型レジスト材料。
【００１７】
【化８】

（式中、Ｒ^１１は水素原子又はメチル基を示し、Ｒ^１２は炭素数１〜８の直鎖状、分岐状又は環状のアルキル基を示す。Ｒ^１３は−ＣＲ^１Ｒ^２ＯＲ^３とは異なる酸不安定基であり、ｄは０又は正数、ｅは正数で、ｄ＋ｅ＝１であり、０．５≦ｅ／（ｄ＋ｅ）≦１．０である。）
【００１８】
〔ＩＶ〕：（Ａ）有機溶剤、
（Ｂ）上記〔Ｉ〕又は〔ＩＩ〕記載のベース樹脂、
（Ｃ）酸発生剤、
（Ｄ）常圧７６０ｍｍＨｇでの沸点が１８０℃以上の炭素数２〜２０の２〜４価のアルコール化合物、
（Ｆ）酸不安定基を有する溶解阻止剤
を含有する化学増幅ポジ型レジスト材料。
【００２０】
以下、本発明につき更に詳しく説明すると、本発明の化学増幅ポジ型レジスト材料は、酸不安定基を有し、酸によりこの酸不安定基が脱離することによってアルカリ可溶性を示す高分子樹脂（ベース樹脂）と、光、電子線等の照射により酸を発生する酸発生剤と、必要により配合される酸不安定基を有する溶解阻止剤と、更に通常、これら成分を溶解する有機溶剤とを含む化学増幅ポジ型レジスト材料において、常圧７６０ｍｍＨｇでの沸点が１８０℃以上、特に１９０℃以上で、２５℃において液状であるアルコール化合物（Ｄ）を配合したものである。このアルコール化合物は、炭素数２〜２０、特に２〜１６の２〜４価のアルコールが好ましく、具体例としては、ポリプロピレングリコール、ポリテトラメチレンエーテルグリコール、ポリエチレングリコール、２−ブチル−２−エチル−１，３−プロパンジオール、ブタンジオールノニルアルコール、ネオペンチルグリコール、トリメチロールエタン、トリメチロールプロパン、チオジグリコール、チオグリセロール、２，２−ジエチル−１，３−プロパンジオール、ジエチレングリコールモノブチルエーテル、トリエチレングリコールモノメチルエーテル、ジエチレングリコールモノメチルエーテル、オクタンジオール、エチレングリコール、ジエチレングリコール、トリエチレングリコール、グリセリンなどが挙げられる。添加量はレジスト組成物の０．０１〜１０％（重量％、以下同じ）の範囲で、好ましくは０．０５〜５％である。添加量が少ないと効果が小さく、添加量が多いと解像性が低下する場合がある。
【００２１】
本発明において、ベース樹脂（Ｂ）としては、フェノール性水酸基の水素原子、特にポリヒドロキシスチレン又はその誘導体の水酸基の水素原子の一部が酸不安定基によって保護されたものが好ましい。この場合、このベース樹脂の重量平均分子量は、５，０００〜１００，０００とすることが好ましく、５，０００に満たないと成膜性、解像性に劣る場合があり、１００，０００を超えると解像性に劣る場合がある。
【００２２】
上記ベース樹脂の酸不安定基は、下記一般式（１）で示されるアセタール基であることが好ましく、ベース樹脂のフェノール性水酸基の水素原子の１０モル％以上、より好ましくは１２モル％以上、更に好ましくは１５モル％以上が式（１）の酸不安定基によって置換されていることが好ましい。なお、ベース樹脂の水酸基の水素原子の式（１）の酸不安定基による置換割合の上限は８０モル％、特に７０モル％であることが好ましい。
【００２３】
【化９】

（式中Ｒ^１、Ｒ^２はそれぞれ独立して水素原子又は炭素数１〜１０の直鎖状、分岐状もしくは環状のアルキル基を示し、Ｒ^６は炭素数１〜１０のヘテロ原子を有していてもよい１価の炭化水素基を示し、Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^２とＲ^３は環を形成してもよく、環を形成する場合にはＲ^１、Ｒ^２、Ｒ^３はそれぞれ炭素数１〜１０の直鎖状又は分岐状のアルキレン基を示す。）
【００２４】
ここで、炭素数１〜１０のアルキル基の例としては、メチル、エチル、ｎ−プロピル、イソプロピル、ｎ−ブチル、イソブチル、ｔｅｒｔ−ブチル、ｎ−ペンチル、イソペンチル、ヘキシル、ノニル、デシル、シクロペンチル、シクロヘキシルなどが挙げられる。
【００２５】
Ｒ^３としては、直鎖状、分岐状又は環状のアルキル基、フェニル基、ｐ−メチルフェニル基、ｐ−エチルフェニル基、ｐ−メトキシフェニル基等のアルコキシ置換フェニル基等の非置換又は置換アリール基、ベンジル基、フェネチル基等のアラルキル基等や、これらの基に酸素原子を有する、或いは炭素原子に結合する水素原子が水酸基に置換されたり、２個の水素原子が酸素原子で置換されてカルボニル基を形成する下記式で示されるようなアルキル基等の基を挙げることができる。
【００２６】
【化１０】

【００２７】
また、Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^２とＲ^３が環を形成する場合、Ｒ^１、Ｒ^２、Ｒ^３はそれぞれ炭素数１〜１０の直鎖状又は分岐状のアルキレン基であるが、環の炭素数は３〜１０、特に４〜８であることが好ましく、更に環には炭素数１〜８、特に１〜４のアルキル基が分岐していてもよい。
【００２８】
具体的に式（１）の酸不安定基としては、１−メトキシエチル基、１−エトキシエチル基、１−ｎ−プロポキシエチル基、１−ｔｅｒｔ−ブトキシエチル基、シクロヘキシロキシエチル基、２−メトキシ−２−プロピル基、２−エトキシ−２−プロピル基、１−メトキシ−１−メチルエチル基、１−エトキシ−１−メチルエチル基などの直鎖状あるいは分岐鎖状アセタール基、テトラヒドロピラニル基、テトラヒドロフラニル基などの環状アセタール基が挙げられる。
【００２９】
なお、酸不安定基としては、上記アセタール基以外の酸不安定基、例えば、ｔｅｒｔ−ブトキシ基のようなアルコキシ基、トリメチルシリル基のようなアルキルシロキシ基、ｔｅｒｔ−ブトキシカルボニル基、ｔｅｒｔ−ブトキシカルボニルメチル基等のｔｅｒｔ−ブチル誘導体の置換基などがポリマー分子中に同時に存在してもかまわないし、ポリマーブレンドによって添加することもできる。
【００３０】
上記ベース樹脂としては、特に下記式（３Ａ）で示されるものが好ましい。
【００３１】
【化１１】

【００３２】
式中、Ｒ^１、Ｒ^２、Ｒ^３は上記と同様の意味を示し、Ｒ^１１は水素原子又はメチル基を示し、Ｒ^１２は炭素数１〜８の直鎖状、分岐状又は環状のアルキル基を示し、Ｒ^１３は上記式（１）とは異なる酸不安定基であり、例えばｔｅｒｔ−ブトキシ基のようなアルコキシ基、トリメチルシリル基のようなアルキルシロキシ基、ｔｅｒｔ−ブトキシカルボニル基、ｔｅｒｔ−ブトキシカルボニルメチル基等のｔｅｒｔ−ブチル誘導体である。
【００３３】
ｃは正数、ｄは０又は正数、ｅは正数であり、ｃ＋ｄ＋ｅ＝１である。なお、ｃ、ｄ、ｅ全体に対するｃの値（式（１）で示される酸不安定基の割合は上述した通りであり、ｄ、ｅは、好適には０≦ｄ／（ｃ＋ｄ＋ｅ）≦０．５、更に好ましくは０≦ｄ／（ｃ＋ｄ＋ｅ）≦０．４、０．４≦ｅ／（ｃ＋ｄ＋ｅ）≦０．９、更に好ましくは０．６≦ｅ／（ｃ＋ｄ＋ｅ）≦０．８である。ｄの全体に対する割合が０．５を超え、ｅの全体に対する割合が０．９を超えるか、或いはｅの全体に対する割合が０．４に満たないと、アルカリ溶解速度のコントラストが小さくなり、解像度が悪くなる場合がある。ｃ、ｄ、ｅはその値を上記範囲内で適宜選定することによりパターンの寸法制御、パターンの形状コントロールを任意に行うことができる。
【００３４】
更に、ベース樹脂（Ｂ）としては、フェノール性水酸基の水素原子、特にポリヒドロキシスチレン又はその誘導体のフェノール性水酸基の水素原子が上述した式（１）の酸不安定基によって上述した割合で部分的に保護され、かつその水酸基の水素原子が０モル％を超える割合、好ましくは１〜３０モル％、更に好ましくは３〜２０モル％が下記一般式（２）で示される酸不安定架橋基によって分子間又は分子内で架橋されたものを使用することができる。なお、その重量平均分子量は５，０００〜１００，０００であることが好ましい。
【００３５】
【化１２】

（式中、Ｒ^４、Ｒ^５は水素原子又は炭素数１〜８の直鎖状、分岐状又は環状のアルキル基を示す。又は、Ｒ^４とＲ^５とは環を形成してもよく、環を形成する場合にはＲ^４、Ｒ^５は炭素数１〜８の直鎖状又は分岐状のアルキレン基を示す。Ｒ^６は炭素数１〜１０の直鎖状又は分岐状のアルキレン基、ｂは０又は１〜１０の整数である。Ａは、ａ価の炭素数１〜５０の脂肪族もしくは脂環式飽和炭化水素基、芳香族炭化水素基又はヘテロ環基を示し、これらの基はヘテロ原子を介在していてもよく、またその炭素原子に結合する水素原子の一部が水酸基、カルボキシル基、カルボニル基又はフッ素原子によって置換されていてもよい。Ｂは−ＣＯ−Ｏ−、−ＮＨＣＯ−Ｏ−又は−ＮＨＣＯＮＨ−を示す。ａは２〜８、ａ’は１〜７の整数である。）
【００３６】
この場合炭素数１〜１０のアルキル基としては、上記と同様のものが挙げられる。また、Ｒ^４とＲ^５とが環を形成する場合、環の炭素数は３〜２０、特に４〜８であり、またその環の一部に炭素数１〜８、特に１〜４のアルキル基が分岐していてもよい。
【００３７】
Ａのａ価の有機基は、具体的には、炭化水素基として好ましくは炭素数１〜５０、特に１〜４０のＯ、ＮＨ、Ｎ（ＣＨ_３）、Ｓ、ＳＯ_２等のヘテロ原子が介在してもよい非置換又は水酸基、カルボキシル基、カルボニル基又はフッ素原子置換のアルキレン基、好ましくは炭素数６〜５０、特に６〜４０のアリーレン基、これらアルキレン基とアリーレン基とが結合した基、上記各基の炭素原子に結合した水素原子が脱離したａ”価（ａ”は３〜８の整数）の基が挙げられ、更にａ価のヘテロ環基、このヘテロ環基と上記炭化水素基とが結合した基などが挙げられる。
【００３８】
具体的に例示すると、Ａとして下記のものが挙げられる。
【００３９】
【化１３】

【００４０】
【化１４】

【００４１】
【化１５】

【００４２】
【化１６】

【００４３】
上記ベース樹脂としては、下記式（３Ｂ）、（３Ｃ）で示されるものが好ましい。
【００４４】
【化１７】

【００４５】
【化１８】

【００４６】
式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^１１、Ｒ^１２、Ｒ^１３は上記と同様の意味を示し、Ｒは式（２ａ）又は（２ｂ）の架橋基である。ｃは正数、ｄは０又は正数、ｅ、ｆは正数であり、ｃ＋ｄ＋ｅ＋ｆ＝１である。なお、ｃ、ｄ、ｅ、ｆの全体に対するｃ、ｆの割合（式（１）で示される酸不安定基の割合、式（２ａ）又は（２ｂ）の架橋基の割合）は上述した通りであり、ｄ、ｅは、好適には０≦ｄ／（ｃ＋ｄ＋ｅ＋ｆ）≦０．５、更に好ましくは０≦ｄ／（ｃ＋ｄ＋ｅ＋ｆ）≦０．４、０．４≦ｅ／（ｃ＋ｄ＋ｅ＋ｆ）≦０．９、更に好ましくは０．６≦ｅ／（ｃ＋ｄ＋ｅ＋ｆ）≦０．８である。ｄの全体に対する割合が０．５を超え、ｅの全体に対する割合が０．９を超えるか、或いはｅの全体に対する割合が０．４に満たないと、アルカリ溶解速度のコントラストが小さくなり、解像度が悪くなる場合がある。ｃ、ｄ、ｅ、ｆはその値を上記範囲内で適宜選定することによりパターンの寸法制御、パターンの形状コントロールを任意に行うことができる。
【００４７】
酸発生剤（Ｃ）としては、例えば、オニウム塩、オキシムスルホン酸誘導体、ヒドロキシイミドスルホン酸エステル誘導体、２，６−ジニトロベンジルスルホン酸誘導体、ピロガロールスルホン酸エステル誘導体、ジアゾナフトキノンスルホン酸エステル誘導体、２，４−ビストリクロロメチル−６−アリール−１，３，５−トリアジン誘導体、α，α’−ビスアリールスルホニルジアゾメタン誘導体、α，α’−ビスアルキルスルホニルジアゾメタン誘導体等を挙げることができる。好ましくは、酸発生剤として下記一般式（４）
（Ｒ^７）_ｆＭＹ （４）
（但し、式中Ｒ^７は同一又は異種の置換又は非置換芳香族基、Ｍはヨードニウム又はスルホニウム、Ｙは置換又は非置換のアルキル又はアリールスルホネートを示す。ｆは２又は３を示す。）
で示されるオニウム塩やα，α’−ビスアリールスルホニルジアゾメタン誘導体、α，α’−ビスアルキルスルホニルジアゾメタン誘導体が用いられる。なお、これら酸発生剤の具体例としては公知のものを挙げることができる。
【００４８】
酸発生剤の添加量は、全ベース樹脂１００重量部に対し０．２〜２０重量部、好ましくは０．５〜１０重量部である。
【００４９】
なお、上記高分子化合物とは別のベース樹脂（Ｅ）として、特に下記一般式（３Ｄ）で示される繰り返し単位を有する重量平均分子量が３，０００〜３００，０００の高分子化合物を配合することができる。これにより、パターンの寸法制御、パターンの形状コントロールを任意に行うことができ、有利である。
【００５０】
【化１９】

【００５１】
式中、Ｒ^１１、Ｒ^１２、Ｒ^１３は上記と同様の意味を示し、ｄは０又は正数、ｅは正数であり、ｄ＋ｅ＝１である。これらの組成比は０≦ｄ／（ｄ＋ｅ）≦０．６、好ましくは０．１≦ｄ／（ｄ＋ｅ）≦０．５、０．５≦ｅ／（ｄ＋ｅ）≦１．０、好ましくは０．６≦ｅ／（ｄ＋ｅ）≦０．９である。
【００５２】
このような高分子化合物は、重量平均分子量が３，０００〜３００，０００、好ましくは５，０００〜３０，０００である必要がある。重量平均分子量が３，０００に満たないとレジスト材料が耐熱性に劣るものとなり、３００，０００を超えるとアルカリ溶解性が低下し、解像性が悪くなる。
【００５３】
更に、このベース樹脂おいて、分子量分布（Ｍｗ／Ｍｎ）が広い場合は低分子量や高分子量のポリマーが存在し、低分子量のポリマーが多く存在すると耐熱性が低下する場合があり、高分子量のポリマーが多く存在するとアルカリに対して溶解し難いものを含み、パターン形成後の裾引きの原因となる場合がある。それ故、パターンルールが微細化するに従ってこのような分子量、分子量分布の影響が大きくなり易いことから、微細なパターン寸法に好適に用いられるレジスト材料を得るには、ベース樹脂の分子量分布は１．０〜２．５、特に１．０〜１．５の狭分散であることが好ましい。
【００５４】
なお、このベース樹脂（Ｅ）の配合量と（Ｂ）成分のベース樹脂との配合割合は、０：１００〜９０：１０の重量比が好ましく、特に０：１００〜５０：５０が好適である。上記ベース樹脂（Ｅ）の配合量が上記重量比より多いと、（Ｂ）成分のベース樹脂による所望の効果が得られない場合がある。
【００５５】
更に、溶解阻止剤（Ｆ）としては、公知のものを使用することができるが、分子内に一つ以上酸によって分解する基（酸不安定基）を有する低分子量の化合物やポリマーが好ましい。低分子量の化合物としては、具体的にビスフェノールＡ誘導体が挙げられるが、特にビスフェノールＡの水酸基をｔｅｒｔ−ブトキシ基やｔｅｒｔ−ブトキシカルボニルオキシ基、エトキシエチル基で置換した化合物が好ましい。溶解阻止剤の添加量は、全ベース樹脂１００重量部に対し０〜５０重量部、好ましくは１０〜３０重量部である。
【００５６】
有機溶剤（Ａ）としては、シクロヘキサノン、メチル−２−ｎ−アミルケトン等のケトン類、３−メトキシブタノール、３−メチル−３−メトキシブタノール、１−メトキシ−２−プロパノール、１−エトキシ−２−プロパノール等のアルコール類、プロピレングリコールモノメチルエーテル、エチレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、エチレングリコールモノエチルエーテル、プロピレングリコールジメチルエーテル、ジエチレングリコールジメチルエーテル等のエーテル類、プロピレングリコールモノメチルエーテルアセテート、プロピレングリコールモノエチルエーテルアセテート、乳酸エチル、ピルビン酸エチル、酢酸ブチル、メチル−３−メトキシプロピオネート、エチル−３−エトキシプロピオネート等のエステル類などが挙げられ、これらの１種類を単独で又は２種類以上を混合して使用することができる。
【００５７】
上記有機溶剤の使用量は特に制限されるものではないが、全ベース樹脂１００重量部に対して１００〜５，０００重量部、特に３００〜２，０００重量部とすることが好ましい。
【００５８】
また、成膜性を向上させるために、界面活性剤を添加することは任意である。具体的には、パーフルオロアルキルポリオキシエチレンエタノール、フッ素化アルキルエステル、パーフルオロアルキルアミンオキサイド、パーフルオロアルキルＥＯ付加物等が挙げられ、吸光性材料としては、ジアリールスルホオキシド、ジアリールスルホン、９，１０−ジメチルアントラセン、９−フルオレノン等が挙げられる。
【００５９】
本発明のポジ型レジスト材料を使用してパターン形成を行うためには、公知のリソグラフィー技術を採用して行うことができ、例えばシリコンウェハー上へスピンコーティング法によりレジスト材料を塗布し、８０〜１５０℃で３０〜２００秒間ベーク（プリベーク）した後、０．５〜２．０μｍ厚みのレジスト膜を形成する。
【００６０】
その後、遠紫外線、電子線、Ｘ線等の光エネルギー線を照射して、７０〜１４０℃で３０〜２００秒間ベーク（ポストエクスポジュアーベーク：ＰＥＢ）し、次いでアルカリ水溶液で現像することにより行うことができる。なお、本発明材料は、特に高エネルギー線の中でも波長２５４〜１９３ｎｍの遠紫外線光、電子線及びＸ線による微細パターン形成に最適であり、ＰＥＢの雰囲気が非乾燥空気気流中であっても乾燥空気あるいは乾燥窒素気流中であっても同様にパターン形成可能である。
【００６１】
【実施例】
以下、実施例と比較例を示して本発明を具体的に説明するが、本発明は下記実施例に限定されるものではない。なお、各例中の部はいずれも重量部である。
【００６２】
〔実施例、比較例〕
高沸点アルコール化合物１〜４とＰｏｌｙｍ．１〜７で示される部分的に水酸基が酸不安定基で保護されたポリヒドロキシスチレンと、ＰＡＧ．１〜３で示される酸発生剤と、ＤＲＩ．１、２で示される溶解阻止剤をプロピレングリコールモノメチルエーテルアセテート（ＰＧＭＥＡ）に溶解し、レジスト組成物を調合し、更に各組成物を０．２μｍのテフロン製フィルターで濾過することにより、レジスト液を調製した。
【００６３】
得られたレジスト液を、シリコンウェハーにスピンコーティングし、ホットプレートを用いて１００℃で９０秒間ベークし、レジスト膜の厚みを０．８μｍの厚さにした。
【００６４】
これをエキシマレーザーステッパー（ニコン社製、ＮＳＲ−２００５ＥＸ８Ａ，ＮＡ−０．５）を用いて露光し、露光後、直ちに乾燥窒素５ｎｌ／ｍｉｎの雰囲気下でホットプレート上で１１０℃で９０秒間ベークを施し、２．３８％のテトラメチルアンモニウムヒドロキシドの水溶液で６０秒間現像を行うことにより、ポジ型のパターンを得た。乾燥窒素５ｎｌ／ｍｉｎの関係湿度は２３℃で５％であった。
【００６５】
次に、同じレジスト膜を、エキシマレーザーステッパー（ニコン社製、ＮＳＲ−２００５ＥＸ８Ａ，ＮＡ−０．５）を用いて露光し、露光後、直ちに関係湿度４５％の雰囲気下でホットプレート上で１１０℃で９０秒間ベークを施し、２．３８％のテトラメチルアンモニウムヒドロキシドの水溶液で６０秒間現像を行い、ポジ型のパターンを得た。
【００６６】
得られたレジストパターンを次のように評価した。結果を表１、２に示す。
評価方法：
関係湿度４５％でＰＥＢを行ったウェハーの０．３５μｍのラインアンドスペースを１：１で解像する露光量を最適露光量（Ｅｏｐ）として、この露光量において分離しているラインアンドスペースの最小線幅を評価レジストの解像度とし、０．３０μｍパターンの形状を、走査型電子顕微鏡を用いて観察した。
【００６７】
乾燥窒素気流中ＰＥＢを行ったウェハーを、上記と同じ露光量の箇所の解像度と０．３０μｍパターン形状を観察した。沸点１８０℃以上のアルコール化合物を添加していない場合、何れもパターンが形成できなかったのに対して、添加した場合はパターン形成が可能であった。
【００６８】
【化２０】

【００６９】
【化２１】

【００７０】
【化２２】

【００７１】
【表１】

ＰＧＭＥＡ：プロピレングリコールモノメチルエーテルアセテート
ＥＬ：乳酸エチル
ＭＭＰ：３−メトキシプロピオン酸メチル
【００７２】
【表２】

【００７３】
【発明の効果】
本発明のレジスト材料は、ＰＥＢの雰囲気が空気気流中であっても、乾燥空気或いは乾燥窒素気流中であっても、良好にパターン形成することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel chemically amplified positive resist material suitable for fine processing technology.
[0002]
Problems to be solved by the prior art and the invention
As the integration and speed of LSIs have become higher and the pattern rules have been required to be finer, far-ultraviolet lithography is promising as a next-generation fine processing technology. Deep-UV lithography can also process 0.3 μm or less, and when a resist material with low light absorption is used, it is possible to form a pattern having a side wall nearly perpendicular to the substrate. In recent years, a technique using a high-brightness KrF excimer laser as a light source of far ultraviolet rays has attracted attention. In order to use this technique as a mass production technique, a resist material having low light absorption and high sensitivity has been demanded. .
[0003]
From this point of view, recently developed acid-catalyzed chemically amplified positive resist materials (described in JP-B-2-27660, JP-A-63-27829, and the like) have sensitivity, resolution, and dry etching resistance. And it has excellent characteristics, and is a particularly promising resist material for deep ultraviolet lithography.
[0004]
However, as a drawback of the chemically amplified resist material, if the standing time from exposure to PEB (Post Exposure Bake) becomes long, the line pattern becomes a T-top shape when the pattern is formed, that is, the upper part of the pattern becomes thick. [PED (Post Exposure Delay)] or a so-called footing phenomenon in which a pattern near a substrate on a basic substrate, particularly a silicon nitride or titanium nitride substrate becomes thicker. The T-top phenomenon is considered to be due to a decrease in the solubility of the resist film surface, and the tailing on the substrate surface is considered to be due to a decrease in the solubility near the substrate. In addition, there is also a problem that a dark reaction of elimination of the acid labile group progresses from exposure to PEB, and the remaining dimension of the line becomes smaller. These are major drawbacks when the chemically amplified resist material is put to practical use. Due to this drawback, the conventional chemically amplified positive resist material has a problem that it is difficult to control the dimensions in a lithography process, and the dimensions are impaired even when processing a substrate using dry etching. Hinsberg, et. al. , J. et al. Photopolym. Sci. Technol. , 6 (4), 535-546 (1993); Kumada, et. al. , J. et al. Photopolym. Sci. Technol. , 6 (4), 571-574 (1993)].
[0005]
In the chemically amplified positive resist material, it is considered that the cause of the problem of PED or footing of the substrate surface largely depends on a basic compound in the air or on the substrate surface. The acid on the resist film surface generated by the exposure reacts and deactivates with the basic compound in the air, and the longer the standing time until PEB is, the more the deactivated acid increases. Is less likely to occur. Therefore, a hardly-solubilized layer is formed on the surface, and the pattern has a T-top shape.
[0006]
Accordingly, an object of the present invention is to provide a chemically amplified positive resist material which solves these problems.
[0007]
Means for Solving the Problems and Embodiments of the Invention
The present inventors have made intensive studies to achieve the above object, and as a result, in particular, a part of the hydrogen atom of the phenolic hydroxyl group is a linear, branched or cyclic acetal group represented by the following general formula (1). It has been found that it is effective to blend an alcohol compound having a boiling point of 180 ° C. or more at a normal pressure of 760 mmHg in a chemically amplified positive resist material using a substituted base resin.
[0008]
That is, in order to solve the above problem, an acid labile group having low activation energy for elimination reaction and high reactivity has been proposed. As the highly reactive leaving substituent, an acetal group is known, and it is known that the elimination reaction of the acetal group requires water. In fact, when the moisture in the PEB where the elimination reaction is accelerated, particularly the humidity in the air is low, there is a problem that the pattern is not formed.
[0009]
In order to solve the above problem, it was found that it was necessary to make the humidity in PEB 30% or more. However, in the g-line and i-line processes, the temperature and air flow in the hot plate and the plate cup are made uniform to increase the temperature control accuracy, and the bake cup is dried to prevent the plate cup from becoming dirty. A process of flowing nitrogen may be performed, at which time the relative humidity of the plate cup may be less than 30%. When a mix-and-match with a conventional g, i-line process is considered, there is a problem that the process is changed. Here, as a result of various studies by the present inventor, the addition of an alcohol compound having a boiling point of 180 ° C. or more at a normal pressure of 760 mmHg promotes the elimination reaction of acetal groups, and provides an atmosphere lacking moisture, such as dry nitrogen. The inventors have found that a pattern can be formed even in an airflow atmosphere, and have accomplished the present invention.
[0010]
Accordingly, the present invention provides the following chemically amplified positive resist material .
[0011]
[ I ]: (A) an organic solvent,
(B) a base resin having a weight average molecular weight of 5,000 to 100,000, in which 10 mol% or more of hydrogen atoms of a phenolic hydroxyl group is substituted by an acid labile group represented by the following general formula (1);
(C) an acid generator,
(D) A chemically amplified positive resist composition comprising a di- or tetra-valent alcohol compound having a boiling point of 180 ° C. or higher and a carbon number of 2 to 20 at 760 mmHg.
[0012]
Embedded image

(Wherein R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and R ³ has a heteroatom having 1 to 10 carbon atoms. And R ¹ and R ² , R ¹ and R ³ , and R ² and R ³ may form a ring, and when forming a ring, R ¹ and R 2 ² and R ³ each represent a linear or branched alkylene group having 1 to 10 carbon atoms.)
[0013]
[ II ]: (A) an organic solvent,
(B) at least 10 mol% of the hydrogen atoms of the phenolic hydroxyl group is replaced by an acid labile group represented by the following general formula (1), and at a rate exceeding 0 mol% of the hydrogen atoms of the phenolic hydroxyl group, (2a) or a base resin having a weight average molecular weight of 5,000 to 100,000 crosslinked intramolecularly and / or intermolecularly by a crosslinking group having a C—O—C group represented by (2b),
(C) an acid generator,
(D) A chemically amplified positive resist composition comprising a di- or tetra-valent alcohol compound having a boiling point of 180 ° C. or higher and a carbon number of 2 to 20 at 760 mmHg.
[0014]
Embedded image

(Wherein R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and R ³ has a heteroatom having 1 to 10 carbon atoms. And R ¹ and R ² , R ¹ and R ³ , and R ² and R ³ may form a ring, and when forming a ring, R ¹ and R 2 ² and R ³ each represent a linear or branched alkylene group having 1 to 10 carbon atoms.)
[0015]
Embedded image

(Wherein, R ⁴ and R ⁵ represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. Alternatively, R ⁴ and R ⁵ may form a ring, When a ring is formed, R ⁴ and R ^{5 each} represent a linear or branched alkylene group having 1 to 8 carbon atoms, and R ⁶ represents a linear or branched alkylene group having 1 to 10 carbon atoms; b is 0 or an integer of 1 to 10. A represents an a-valent aliphatic or alicyclic saturated hydrocarbon group having 1 to 50 carbon atoms, an aromatic hydrocarbon group or a heterocyclic group, and these groups are shown. May have a heteroatom interposed, and a part of the hydrogen atom bonded to the carbon atom may be substituted by a hydroxyl group, a carboxyl group, a carbonyl group or a fluorine atom, and B is -CO-O-, -NHCO-O- or -NHCONH-, wherein a is an integer of 2 to 8 and a 'is an integer of 1 to 7 .)
[0016]
[ III ]: (A) an organic solvent,
(B) the base resin according to the above [ I ] or [ II ],
(C) an acid generator,
(D) a divalent to tetravalent alcohol compound having 2 to 20 carbon atoms and a boiling point of 180 ° C. or higher at normal pressure of 760 mmHg;
(E) A chemically amplified positive resist material comprising a polymer compound having a repeating unit represented by the following general formula (3D) and having a weight average molecular weight of 3,000 to 300,000.
[0017]
Embedded image

(Wherein, R ¹¹ represents a hydrogen atom or a methyl group, R ¹² represents a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms. R ¹³ represents —CR ¹ R ² OR ³ (D is 0 or a positive number, e is a positive number, d + e = 1, and 0.5 ≦ e / (d + e) ≦ 1.0.)
[0018]
[ IV ]: (A) an organic solvent,
(B) the base resin according to the above [ I ] or [ II ],
(C) an acid generator,
(D) a divalent to tetravalent alcohol compound having 2 to 20 carbon atoms and a boiling point of 180 ° C. or higher at normal pressure of 760 mmHg;
(F) A chemically amplified positive resist material containing a dissolution inhibitor having an acid labile group.
[0020]
Hereinafter, the present invention will be described in more detail. The chemically amplified positive resist composition of the present invention has a polymer resin having an acid labile group and exhibiting alkali solubility when the acid labile group is eliminated by an acid ( A base resin), an acid generator that generates an acid upon irradiation with light, an electron beam, or the like, a dissolution inhibitor having an acid labile group incorporated as necessary, and more usually an organic solvent that dissolves these components. A chemically amplified positive resist composition containing an alcohol compound (D) having a boiling point at normal pressure of 760 mmHg of 180 ° C. or higher, particularly 190 ° C. or higher, and liquid at 25 ° C. The alcohol compounds 2 to 20 carbon atoms, particularly preferably a divalent to tetravalent alcohol having 2 to 16, specific examples, polypropylene glycol, polytetramethylene ether glycol, polyethylene glycol, 2-butyl-2-ethyl - 1,3-propanediol, butanediol nonyl alcohol, neopentyl glycol, trimethylolethane, trimethylolpropane , thiodiglycol, thioglycerol, 2,2-diethyl-1,3-propanediol, diethylene glycol monobutyl ether, triethylene Glycol monomethyl ether, diethylene glycol monomethyl ether, octanediol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin and the like can be mentioned. The amount of addition is in the range of 0.01 to 10% (% by weight, the same applies hereinafter) of the resist composition, preferably 0.05 to 5%. If the amount is small, the effect is small, and if the amount is large, the resolution may be reduced.
[0021]
In the present invention, the base resin (B) is preferably a resin in which a hydrogen atom of a phenolic hydroxyl group, particularly a part of a hydrogen atom of a hydroxyl group of polyhydroxystyrene or a derivative thereof is protected by an acid labile group. In this case, the weight average molecular weight of the base resin is preferably from 5,000 to 100,000. If it is less than 5,000, the film formability and the resolution may be poor, and may exceed 100,000. And poor resolution in some cases.
[0022]
The acid labile group of the base resin is preferably an acetal group represented by the following general formula (1), and is preferably at least 10 mol%, more preferably at least 12 mol% of the hydrogen atom of the phenolic hydroxyl group of the base resin. More preferably, at least 15 mol% is substituted by the acid labile group of the formula (1). The upper limit of the substitution ratio of the hydrogen atom of the hydroxyl group of the base resin by the acid labile group of the formula (1) is preferably 80 mol%, particularly preferably 70 mol%.
[0023]
Embedded image

(Wherein R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and R ⁶ has a heteroatom having 1 to 10 carbon atoms. And R ¹ and R ² , R ¹ and R ³ , and R ² and R ³ may form a ring, and when forming a ring, R ¹ and R 2 ² and R ³ each represent a linear or branched alkylene group having 1 to 10 carbon atoms.)
[0024]
Here, examples of the alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, hexyl, nonyl, decyl, cyclopentyl, Cyclohexyl and the like.
[0025]
R ³ is an unsubstituted or substituted aryl such as a linear, branched or cyclic alkyl group, phenyl group, p-methylphenyl group, p-ethylphenyl group, and alkoxy-substituted phenyl group such as p-methoxyphenyl group. Group, benzyl group, aralkyl group such as phenethyl group, or those groups having an oxygen atom, or a hydrogen atom bonded to a carbon atom is substituted with a hydroxyl group, or two hydrogen atoms are substituted with an oxygen atom. Examples of the carbonyl group include groups such as an alkyl group represented by the following formula.
[0026]
Embedded image

[0027]
When R ¹ and R ² , R ¹ and R ³ , and R ² and R ³ form a ring, R ¹ , R ² , and R ³ each represent a linear or branched alkylene having 1 to 10 carbon atoms. Although it is a group, the number of carbon atoms in the ring is preferably 3 to 10, particularly 4 to 8, and the ring may be branched by an alkyl group having 1 to 8 carbon atoms, especially 1 to 4 carbon atoms.
[0028]
Specifically, the acid labile group of the formula (1) includes a 1-methoxyethyl group, a 1-ethoxyethyl group, a 1-n-propoxyethyl group, a 1-tert-butoxyethyl group, a cyclohexyloxyethyl group, Linear or branched acetal groups such as methoxy-2-propyl group, 2-ethoxy-2-propyl group, 1-methoxy-1-methylethyl group, 1-ethoxy-1-methylethyl group, and tetrahydropyranyl And a cyclic acetal group such as a tetrahydrofuranyl group.
[0029]
Examples of the acid labile group include acid labile groups other than the acetal group described above, for example, an alkoxy group such as a tert-butoxy group, an alkylsiloxy group such as a trimethylsilyl group, a tert-butoxycarbonyl group, and a tert-butoxycarbonyl group. Substituents of a tert-butyl derivative such as a methyl group may be present in the polymer molecule at the same time, or may be added by a polymer blend.
[0030]
As the base resin, a resin represented by the following formula (3A) is particularly preferable.
[0031]
Embedded image

[0032]
In the formula, R ¹ , R ² and R ³ have the same meanings as described above, R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents a linear, branched or cyclic alkyl having 1 to 8 carbon atoms. R ¹³ is an acid labile group different from the above formula (1), for example, an alkoxy group such as a tert-butoxy group, an alkylsiloxy group such as a trimethylsilyl group, a tert-butoxycarbonyl group, a tert- It is a tert-butyl derivative such as a butoxycarbonylmethyl group.
[0033]
c is a positive number, d is 0 or a positive number, e is a positive number, and c + d + e = 1. The value of c with respect to the whole of c, d and e (the ratio of the acid labile group represented by the formula (1) is as described above, and d and e are preferably 0 ≦ d / (c + d + e) ≦ 0 0.5, more preferably 0 ≦ d / (c + d + e) ≦ 0.4, 0.4 ≦ e / (c + d + e) ≦ 0.9, more preferably 0.6 ≦ e / (c + d + e) ≦ 0.8. When the ratio of d to the whole is more than 0.5 and the ratio of e to the whole is more than 0.9, or when the ratio of e to the whole is less than 0.4, the contrast of the alkali dissolution rate becomes small, The resolution may be deteriorated, and the dimensions of the pattern and the shape of the pattern can be arbitrarily controlled by appropriately selecting the values of c, d, and e within the above ranges.
[0034]
Further, as the base resin (B), the hydrogen atoms of the phenolic hydroxyl group, particularly the hydrogen atoms of the phenolic hydroxyl group of polyhydroxystyrene or a derivative thereof, are partially formed in the above-mentioned ratio by the acid labile group of the above formula (1). And more than 0 mol%, preferably 1 to 30 mol%, more preferably 3 to 20 mol%, of the hydroxyl groups are protected by an acid-labile crosslinking group represented by the following general formula (2). Those crosslinked between molecules or intramolecularly can be used. In addition, it is preferable that the weight average molecular weight is 5,000-100,000.
[0035]
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(Wherein, R ⁴ and R ⁵ represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. Alternatively, R ⁴ and R ⁵ may form a ring, When a ring is formed, R ⁴ and R ^{5 each} represent a linear or branched alkylene group having 1 to 8 carbon atoms, and R ⁶ represents a linear or branched alkylene group having 1 to 10 carbon atoms; b is 0 or an integer of 1 to 10. A represents an a-valent aliphatic or alicyclic saturated hydrocarbon group having 1 to 50 carbon atoms, an aromatic hydrocarbon group or a heterocyclic group, and these groups are shown. May have a heteroatom interposed, and a part of the hydrogen atom bonded to the carbon atom may be substituted by a hydroxyl group, a carboxyl group, a carbonyl group or a fluorine atom, and B is -CO-O-, -NHCO-O- or -NHCONH-, wherein a is an integer of 2 to 8 and a 'is an integer of 1 to 7 .)
[0036]
In this case, examples of the alkyl group having 1 to 10 carbon atoms include the same as described above. When R ⁴ and R ⁵ form a ring, the ring has 3 to 20, especially 4 to 8 carbon atoms, and a part of the ring has 1 to 8 carbon atoms, particularly 1 to 4 carbon atoms. The groups may be branched.
[0037]
As the a-valent organic group of A, specifically, as a hydrocarbon group, a heteroatom such as O, NH, N (CH ₃ ), S, or SO ₂ having 1 to 50 carbon atoms, particularly 1 to 40 carbon atoms is preferable. An unsubstituted or hydroxyl group, a carboxyl group, a carbonyl group or a fluorine atom-substituted alkylene group which may be interposed, preferably an arylene group having 6 to 50, particularly 6 to 40 carbon atoms, a group in which these alkylene groups and an arylene group are bonded. And an a ″ -valent group (a ″ is an integer of 3 to 8) in which a hydrogen atom bonded to a carbon atom of each of the above groups has been eliminated. Further, an a-valent heterocyclic group, And a group bonded to a hydrogen group.
[0038]
Specific examples include the following.
[0039]
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[0040]
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[0041]
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[0042]
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[0043]
As the base resin, those represented by the following formulas (3B) and (3C) are preferable.
[0044]
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[0045]
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[0046]
In the formula, R ¹ , R ² , R ³ , R ¹¹ , R ¹² , and R ¹³ have the same meaning as described above, and R is a crosslinking group of the formula (2a) or (2b). c is a positive number, d is 0 or a positive number, e and f are positive numbers, and c + d + e + f = 1. The ratio of c and f to the total of c, d, e and f (the ratio of the acid labile group represented by the formula (1) and the ratio of the crosslinking group of the formula (2a) or (2b)) is as described above. And d and e are preferably 0 ≦ d / (c + d + e + f) ≦ 0.5, more preferably 0 ≦ d / (c + d + e + f) ≦ 0.4, 0.4 ≦ e / (c + d + e + f) ≦ 0. 9, more preferably 0.6 ≦ e / (c + d + e + f) ≦ 0.8. When the ratio of d to the whole is more than 0.5 and the ratio of e to the whole is more than 0.9, or when the ratio of e to the whole is less than 0.4, the contrast of the alkali dissolution rate becomes small and the resolution becomes low. May be worse. By appropriately selecting the values of c, d, e, and f within the above ranges, it is possible to arbitrarily control the pattern dimension and the pattern shape.
[0047]
Examples of the acid generator (C) include onium salts, oxime sulfonic acid derivatives, hydroxyimide sulfonic acid ester derivatives, 2,6-dinitrobenzyl sulfonic acid derivatives, pyrogallol sulfonic acid ester derivatives, diazonaphthoquinone sulfonic acid ester derivatives, , 4-bistrichloromethyl-6-aryl-1,3,5-triazine derivatives, α, α′-bisarylsulfonyldiazomethane derivatives, α, α′-bisalkylsulfonyldiazomethane derivatives, and the like. Preferably, the following general formula (4) is used as the acid generator.
(R ⁷ ) _f MY (4)
(Wherein, R ⁷ represents the same or different substituted or unsubstituted aromatic group, M represents iodonium or sulfonium, Y represents a substituted or unsubstituted alkyl or aryl sulfonate, and f represents 2 or 3.)
And α, α′-bisarylsulfonyldiazomethane derivatives and α, α′-bisalkylsulfonyldiazomethane derivatives. Note that specific examples of these acid generators include known ones.
[0048]
The addition amount of the acid generator is 0.2 to 20 parts by weight, preferably 0.5 to 10 parts by weight based on 100 parts by weight of the total base resin.
[0049]
In addition, as a base resin (E) different from the above-mentioned polymer compound, a polymer compound having a repeating unit represented by the following general formula (3D) and having a weight-average molecular weight of 3,000 to 300,000 is particularly compounded. Can be. Thereby, it is possible to arbitrarily control the dimension of the pattern and the shape of the pattern, which is advantageous.
[0050]
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[0051]
In the formula, R ¹¹ , R ¹² and R ¹³ have the same meaning as described above, d is 0 or a positive number, e is a positive number, and d + e = 1. These composition ratios are 0 ≦ d / (d + e) ≦ 0.6, preferably 0.1 ≦ d / (d + e) ≦ 0.5, 0.5 ≦ e / (d + e) ≦ 1.0, preferably 0. 0.6 ≦ e / (d + e) ≦ 0.9.
[0052]
Such a polymer compound needs to have a weight average molecular weight of 3,000 to 300,000, preferably 5,000 to 30,000. If the weight average molecular weight is less than 3,000, the resist material will have poor heat resistance, and if it exceeds 300,000, the alkali solubility will be reduced and the resolution will be poor.
[0053]
Further, in this base resin, when the molecular weight distribution (Mw / Mn) is wide, a low molecular weight or high molecular weight polymer is present, and when a large amount of low molecular weight polymer is present, heat resistance may be reduced, and If a large amount of the polymer is present, some of the polymer may be difficult to dissolve in alkali, and may cause tailing after pattern formation. Therefore, as the pattern rule becomes finer, the influence of such molecular weight and molecular weight distribution tends to increase. Therefore, in order to obtain a resist material suitably used for fine pattern dimensions, the molecular weight distribution of the base resin must be as follows. A narrow dispersion of 0 to 2.5, particularly 1.0 to 1.5 is preferable.
[0054]
The compounding amount of the base resin (E) and the compounding ratio of the component (B) to the base resin are preferably 0: 100 to 90:10, more preferably 0: 100 to 50:50. . If the amount of the base resin (E) is more than the above weight ratio, the desired effect of the base resin as the component (B) may not be obtained.
[0055]
Further, as the dissolution inhibitor (F), known compounds can be used, but a low molecular weight compound or polymer having at least one group decomposed by an acid (acid labile group) in the molecule is preferable. Specific examples of the low-molecular-weight compound include bisphenol A derivatives, and a compound in which the hydroxyl group of bisphenol A is substituted with a tert-butoxy group, a tert-butoxycarbonyloxy group, or an ethoxyethyl group is particularly preferable. The addition amount of the dissolution inhibitor is 0 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the total base resin.
[0056]
Examples of the organic solvent (A) include ketones such as cyclohexanone and methyl-2-n-amyl ketone, 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-. Alcohols such as propanol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, ethers such as diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl-3-methoxypropionate, ethyl-3-ethoxy It includes such esters propionate or the like, it is possible to use these singly or in combination of two or more kinds.
[0057]
The amount of the organic solvent used is not particularly limited, but is preferably 100 to 5,000 parts by weight, particularly preferably 300 to 2,000 parts by weight, based on 100 parts by weight of the total base resin.
[0058]
It is optional to add a surfactant in order to improve film formability. Specific examples include perfluoroalkyl polyoxyethylene ethanol, fluorinated alkyl esters, perfluoroalkyl amine oxides, perfluoroalkyl EO adducts, and the like, and as the light absorbing material, diaryl sulfoxide, diaryl sulfone, 9, 10-dimethylanthracene, 9-fluorenone and the like.
[0059]
In order to form a pattern using the positive resist material of the present invention, a known lithography technique can be employed. For example, a resist material is applied on a silicon wafer by a spin coating method, After baking (prebaking) at 30 ° C. for 30 to 200 seconds, a resist film having a thickness of 0.5 to 2.0 μm is formed.
[0060]
Thereafter, irradiation is performed with light energy rays such as far ultraviolet rays, electron beams, and X-rays, baking (post-exposure baking: PEB) at 70 to 140 ° C. for 30 to 200 seconds, and then developing with an alkaline aqueous solution. be able to. The material of the present invention is particularly suitable for forming a fine pattern using far ultraviolet light having a wavelength of 254 to 193 nm, an electron beam, and an X-ray, even among high energy rays. A pattern can be similarly formed even in air or a dry nitrogen stream.
[0061]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. All parts in each example are parts by weight.
[0062]
(Examples, Comparative Examples)
High boiling alcohol compounds 1-4 and Polym. Polyhydroxystyrene in which a hydroxyl group is partially protected with an acid labile group represented by PAG. Acid generators represented by DRI. By dissolving the dissolution inhibitors represented by 1 and 2 in propylene glycol monomethyl ether acetate (PGMEA), preparing a resist composition, and further filtering each composition with a 0.2 μm Teflon filter, the resist solution was removed. Prepared.
[0063]
The obtained resist solution was spin-coated on a silicon wafer and baked at 100 ° C. for 90 seconds using a hot plate to reduce the thickness of the resist film to 0.8 μm.
[0064]
This was exposed using an excimer laser stepper (manufactured by Nikon Corporation, NSR-2005EX8A, NA-0.5). Immediately after the exposure, baking was performed at 110 ° C. for 90 seconds on a hot plate in an atmosphere of dry nitrogen 5 nl / min. Then, development was performed for 60 seconds with a 2.38% aqueous solution of tetramethylammonium hydroxide to obtain a positive pattern. The relative humidity of 5 nl / min of dry nitrogen was 5% at 23 ° C.
[0065]
Next, the same resist film was exposed using an excimer laser stepper (manufactured by Nikon Corporation, NSR-2005EX8A, NA-0.5). Immediately after the exposure, 110 ° C. on a hot plate in an atmosphere having a relative humidity of 45%. And baked for 90 seconds, and developed with a 2.38% aqueous solution of tetramethylammonium hydroxide for 60 seconds to obtain a positive pattern.
[0066]
The obtained resist pattern was evaluated as follows. The results are shown in Tables 1 and 2.
Evaluation method:
The optimal exposure (Eop) is defined as the exposure that resolves the 0.35 μm line and space of the wafer subjected to PEB at 45% relative humidity at a ratio of 1: 1. Using the line width as the resolution of the evaluation resist, the shape of the 0.30 μm pattern was observed using a scanning electron microscope.
[0067]
The wafer subjected to PEB in a dry nitrogen stream was observed for the same resolution and 0.30 μm pattern shape at the same exposure amount as described above. When no alcohol compound having a boiling point of 180 ° C. or higher was added, no pattern could be formed, whereas when an alcohol compound was added, a pattern could be formed.
[0068]
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[0069]
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[0070]
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[0071]
[ Table 1 ]

PGMEA: propylene glycol monomethyl ether acetate EL: ethyl lactate MMP: methyl 3-methoxypropionate
[Table 2]

[0073]
【The invention's effect】
The resist material of the present invention can favorably form a pattern even when the PEB atmosphere is in an air stream, or in a dry air or dry nitrogen stream.

Claims (4)

(A) an organic solvent,
(B) a base resin having a weight average molecular weight of 5,000 to 100,000, in which 10 mol% or more of hydrogen atoms of a phenolic hydroxyl group is substituted by an acid labile group represented by the following general formula (1);

(Wherein R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and R ³ has a heteroatom having 1 to 10 carbon atoms. And R ¹ and R ² , R ¹ and R ³ , and R ² and R ³ may form a ring, and when forming a ring, R ¹ and R 2 ² and R ³ each represent a linear or branched alkylene group having 1 to 10 carbon atoms.)
(C) an acid generator,
(D) A chemically amplified positive resist composition comprising a di- or tetra-valent alcohol compound having a boiling point of 180 ° C. or higher and a carbon number of 2 to 20 at 760 mmHg. (A) an organic solvent,
(B) at least 10 mol% of the hydrogen atoms of the phenolic hydroxyl group is replaced by an acid labile group represented by the following general formula (1), and at a rate exceeding 0 mol% of the hydrogen atoms of the phenolic hydroxyl group, (2a) or a base resin having a weight average molecular weight of 5,000 to 100,000 crosslinked intramolecularly and / or intermolecularly by a crosslinking group having a C—O—C group represented by (2b),

(Wherein R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and R ³ has a heteroatom having 1 to 10 carbon atoms. And R ¹ and R ² , R ¹ and R ³ , and R ² and R ³ may form a ring, and when forming a ring, R ¹ and R 2 ² and R ³ each represent a linear or branched alkylene group having 1 to 10 carbon atoms.)

(Wherein, R ⁴ and R ⁵ represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. Alternatively, R ⁴ and R ⁵ may form a ring, When a ring is formed, R ⁴ and R ^{5 each} represent a linear or branched alkylene group having 1 to 8 carbon atoms, and R ⁶ represents a linear or branched alkylene group having 1 to 10 carbon atoms; b is 0 or an integer of 1 to 10. A represents an a-valent aliphatic or alicyclic saturated hydrocarbon group having 1 to 50 carbon atoms, an aromatic hydrocarbon group or a heterocyclic group, and these groups are shown. May have a heteroatom interposed, and a part of the hydrogen atom bonded to the carbon atom may be substituted by a hydroxyl group, a carboxyl group, a carbonyl group or a fluorine atom, and B is -CO-O-, -NHCO-O- or -NHCONH-, wherein a is an integer of 2 to 8 and a 'is an integer of 1 to 7 .)
(C) an acid generator,
(D) A chemically amplified positive resist composition comprising a di- or tetra-valent alcohol compound having a boiling point of 180 ° C. or higher and a carbon number of 2 to 20 at 760 mmHg. (A) an organic solvent,
(B) the base resin according to claim 1 or 2 ,
(C) an acid generator,
(D) a divalent to tetravalent alcohol compound having 2 to 20 carbon atoms and a boiling point of 180 ° C. or higher at normal pressure of 760 mmHg;
(E) A chemically amplified positive resist material comprising a polymer compound having a repeating unit represented by the following general formula (3D) and having a weight average molecular weight of 3,000 to 300,000.

(Wherein, R ¹¹ represents a hydrogen atom or a methyl group, R ¹² represents a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms. R ¹³ represents —CR ¹ R ² OR ³ (D is 0 or a positive number, e is a positive number, d + e = 1, and 0.5 ≦ e / (d + e) ≦ 1.0.) (A) an organic solvent,
(B) the base resin according to claim 1 or 2 ,
(C) an acid generator,
(D) a divalent to tetravalent alcohol compound having 2 to 20 carbon atoms and a boiling point of 180 ° C. or higher at normal pressure of 760 mmHg;
(F) A chemically amplified positive resist material containing a dissolution inhibitor having an acid labile group.